Replacing lower control arm bushings
 

We just took a road trip in the wagon, a w123, about 350 miles each way. When we got there, I noticed a creaking sound from the front drivers side. After a little investigation, it seems to be the LCA bushing on the drivers side. We had to drive it home a few days later, so no time for any repairs, so I just took it easy on the bumps on the way home. I didn't seem to get any worse once we got home, but it didn't get any better. It creaks when you push down on the front end, and you can kind of feel the creaking when you touch the bushing area.

Well, I'm pretty green when it comes to this suspension work. I know I need a spring compressor to get the LCA arm off, but are there any other special tools, presses, pullers that I'll need? I figure I'll replace the ball joint while I'm there and the guide rod/strut as well. That strut/rod has been clunking for a while when I brake, and I was wondering if that's what took out the LCA bushing...and what usually needs to be replaced with the guide rod?

Also, is this job a huge PITA? I just got the 240D back from the mechanic for doing (costly) work that I couldn't do and I'd like to do this myself to make myself feel better.

I appreciate the info.
-Geoff

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im doing this right now. i dont know what a flaring tool looks like, but you'll need one for the metal sleeve insert that goes into the LCA bushing itself

Some way to pop ball joints. My neighbor can do them with a hammer, but I couldn't get the knack and ended up getting a ball joint popper from NAPA. I then had to grinding the bottom teeth to a point so it'd slip in between the ball joint boot and the knuckle.

You'll also need a special tool for R&R of the ball joint from the knuckle. I used my wallet at a local alignment shop since I was getting tired of the job after a couple of weeks worth of evenings.

IIRC, you can do the LCA bushing and lower ball joint as separate operations and thereby skip the spring removal pain, but then you can't use your wallet for any of the work to make it a little easier. I'm not sure how you're supposed to get the ball joint out of the knuckle when you do it that way, but there must be a way because the FSM says you can.

What work didn't you think you could handle yourself? If we're talking engine rebuild or related, then you're still in the game. If you're talking repacking front wheel bearings, don't attempt this.

I won't bore you with all the things I could say about this job, just suffice it to say.. that there is the spring to R&R, which is its own white-knuckle PITA, and about a bazillion bolts to remove, reinstall and torque. It is a lot of work, which is why mechanics charge so much for the work, but it isn't impossible. It was certainly the largest auto repair project I've undertaken to date, but I never once felt like I was stuck in a jam that I might not be able to get myself out of.

Whether you can do it or not is another question. Just keep in mind, once you start, you're pretty much committed to some degree of reassembly before you can move the car anywhere (like to your mechanic to bail you out).

link to what you are getting into
 

http://www.peachparts.com/shopforum/diesel-discussion/179284-write-up-ball-joints-lower-control-arm-bushings-tool-review-pics.html?highlight=pics

The above link is a write-up I did that shows what you are getting into.

Though it is a pay-for site, www.pindelski.com has a step by step pictorial / guide on rebuilding the front end on a W126 mercedes (W123 won't be that much different). That is where I learned what the heck I was doing!

You cannot do the LCA bearing without a spring compressor. If you do get the LCA off, replace the strut rod -> LCA bearing. Its cheap and can only be done with the spring off. Everything else can be done with spring on. As far as strut rod, the mount is not cheap but easy to do with the spring off. Ball joint does not require the special tool but it will certainly make it easier.

Thanks for all the info. I guess my initial plan was to remove the LCA and bring it to the mechanic for bushing and ball joint replacement. So I'm looking at renting a spring compressor and a pitman arm puller, but I guess that eliminates a press, ball joint popper, and the special tool for getting the bushing in/out of the control arm.

The work that I just had the mechanic do involved welding, which counts me out :( The steering box mount on the frame was cracked and broken, and he had to make a new mount and weld it to the frame. He did a really good job (he let me peek in a few times along the way), but it was several hours labor.

As for the strut rod, I saw a rebuilt kit listed in the parts section, it looks like its for the mount, so I'll plan on getting that and a new bushing for the other end at the control arm as well.

How urgent of a deal is this? Right now I'm still driving around town for short trips, but I don't know whether I should stay off the highway for the long trips.

Thanks again...oh and that's a great write-up bodyart, that's what I was looking for. It would be beneficial in the DIY section.

The ball joint is in the knuckle, the bushing is in the LCA. The bushing is trivial to replace if you have a vise and a few odds and ends. The knuckle typically involved beating the old joint out and then using a press to press the new one in.

I looked at pittmal arm pullers and if you can get them to get a grip on the piece (most are rounded on the underside), they should do nicely. I know for certain that gear pullers won't work because the the jaws can't keep a grip on the curved undersurface.

I removed the old bushing with a big drill, a vise, a crowbar and a hammer. Hold it in the vise, drill out the inner aluminum tube and then catch the metal edge by the LCA with the crowbar and pound onthe crowbar to extract the bushing half from the arm. Pound out the other side of the bushing with a block of wood and the hammer.

That makes sense. Welding I wouldn't do either (yet), but this I'd do again if I had to -- except for the spring compressor, its just a bunch of bolts.

Do you feel safe driving it around? If not, then replace it sooner rather than later. If you feel safe, then get under there and try and see what is sliding against what (that probably isn't supposed to be sliding at all) and decide if you still think its safe. From here, about all I can say is to replace it immediately as I know that'll keep you safe -- maybe you'll be OK if you wait a while, but I know you'll be safe if you don't wait to replace it.

I'm glad somebody was able to point you at a good writeup. I took lots of pictures as I did mine, but still haven't gotten around to writing it up (not that anybody would really care.. I write them up mainly for my own future reference).

You can rent the tools for all of it except the spring compressor from autozone/advanced auto. NAPA sells a knockoff ball joint remover for cheap but i dont know anyone who has successfully used it.